In this code above, the Piechart element appears when I switch to the second segment. I can't figure out how to hide it, remove it from the view, delete it, or whatever is needed to make it not appear in the second segment.

As you are reinstantiating the PiChart object in the cellForRowAtIndexPath method, you no longer have a reference to the PiChart that you can see on your screen. Saying that, the cell should be re-created at this point but I have known that not to happen. Although this is not an ideal solution by any means it is worth trying just to confirm suspicions.

As much as I hate climbing into the view hierarchy like this, if you have lost the reference to the object it can sometimes be the better approach.